Switching apparatus



Patented July 2l, l1942 SWITCHING APPARATUS Kirk A. Oplinger, Verona, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 5, 1941, Serial No. 387,097

Claims.

This invention relates to electrical switching apparatus.

The object of this invention is to provide in a switching apparatus a well for the switching fluid made up of contact members and insulating spacer members bonded together with a suitable bonding material.

Another object of this invention is to utilize a plurality of alternately stacked conductor members and spacer members bonded together with a suitable bonding material for providing a Well in which a switching fluid is disposed to progressively bridge the contact members.

A more specific object of this invention is to provide in a switching apparatus a well for the switching uid made up of contact members and insulating spacer members bonded together with glass, the contact members extending outwardly from the well in staggered relation to one another to facilitate the making of Velectrical connections therewith.

Other objects of this invention will become apparent from the following description, when taken in conjunction with the accompanying drawing in which:

Figure 1 is a View n perspective of the switching apparatus of this invention;

Fig. 2 is a view in section taken along the line II-II of Fig. 1

Fig. 3 is a plan view of some of the cooperating elements of the switching apparatus embodying the teachings of this invention; and

Fig. 4 is a schematic diagram illustrating the use of the switching apparatus of this invention in a regulating system.

Referring to Figs. 1 and 2, there is illustrated a switching apparatus I0 embodying the teachings of this invention. The switching apparatus I0 comprises a plurality of elongated conductor members or leaves I2 and insulating spacer members I4 stacked alternately in assembled relation.

The conductor members I2 may be of any suitable conducting metal or as in a preferred embodiment of this invention are preferably formed of an 4alloy known to the trade as Kovar. Kovar is an iron base alloy composed essentially of nickel, cobalt and iron with the nickel plus cobalt content ranging from 40 to 55% of the alloy when the cobalt content ranges from 12 to 33% and the balance substantially iron, as described and claimed in Patent 1,942,260, issued January 2, 1934, to Howard Scott. In the preferred embodiment of this invention the elongated conductor members I 2 are substantially rectangular in lshape having one side tapered to provide a terminal as shown in Figs. 1 and 3 of the drawing. The members I2 are preferably thin, being of the order of gif of an inch thick. As illustrated in Fig. 3, each of the leaves or conductor members I2 is provided with a plurality of openings I6, I8 and 20, the purpose of which will be explained more fully hereinafter.

The spacer members I4 may be of any suitable insulating material and in this embodiment are preferably formed of a ceramic insulating material. The ceramic spacer members I4 are provided withV a Vcentral Vopening therein of a size corresponding to the opening I6 in the leaf member I2 and have a thickness equal to the spacing factor Which'it Vis desired to maintain between the conductor members I2. The central opening of the ceramic spacer members I4 cooperates with the opening I 6 in the conductor members I2 when they are stacked alternately therewith to provide a well throughout the stacked assembly.

Referring to Fig. 2, the apparatus of this invention will be described in detail by reference to a method of assembling the component elements thereof. In `this figure a base portion formed of a plurality vof'annular members 22, 24 and 26 each of which has a central opening for cooperating with the' well formed by the conductor members I2 'and the spacer members I4 and forming an extension thereof are positioned for receiving the conductor members and the spacer members. These annular members are preferably sealed to each otherV to prevent leaks therebetween or where desired a single solid base member can be employed in place of the three an- 'nul-ar members. Each of the annular members also hasja plurality of openings I8 therein corresponding to the openings I8 formed in the conductor members I2. With the annular members `22, 24 and 26 thus assembled, a ceramic tubular member '28 is positioned in each of the openings I8 ofthe base portion and where desired a carbonrod may be positioned in thev central opening formed in the base portion. The'carbon rod (not illustrated) is provided for aiding in the positioning of the ceramic spacer members with respect to the centraln opening lli in the conductor members I2;

With the ceramic tubes 2'8 in position and the carbon rod (not shown) disposed in the central opening, a ceramic Spacer member I4 is positioned aboutv the carbon rod and seated on the annular member 22. A yconducting member I2 is then slipped over the ceramic tubes 28 and the carbon rod (not. shown) to seat against the ce- Y ramic spacer I4 with its tapered end projecting from the stack. Spacer members I4 and conductor members I2 are added to the stack in alternate relation until the desired number of conductor members or leaves are added to the assembly. Referring to Fig. 1, it is seen that as the conductor members I2 are stacked alternately with the spacer members I4, the projecting end of each succeeding conductor leaf member I2 extending outwardly yfrom the stack at a different side, every fifth conductor member being so reversed that the tapered end of no two successive conductor members extending from one side f the stack are in alignment. B-y positioning the conductor members I2 in this manner, a plurality of staggered terminals are provided for making electrical connections thereto from the electrical apparatus with which it is to be associated. The ceramic tubes 28 and the carbon rod (not shown)` thus function in the assembly of the elements as guide members 01', forming thestack. In` all cases, the stack begins. and ends with one of. the ceramic insulating members I4. to insulate the conductor members from the associated terminal plates.

In addition to the spacer members I4. positioned alternately with respect to the conductor members I2, a bondingmediumW also. disposed between each of theconductor members I-Z adjacent each of the spacer members. I4.. In theparticular embodiment of this invention being described, glassisemployed as the bonding medium. The glass is usually'in the formof a glass washer (notA shown) of a size suitable for placing it about the periphery of the spacer member I4.

A preferred glass for this use is a boro-silicate glasshaving a coeflicient of expansion approximating that. `of Kovar and which readily Wetsthe alloyI of the 'conductor leaves and may` be sealed thereto as well asto the ceramic spacer` member I4. The glass employedV in this embodiment conf-y sisted of about,6.4.% by weight ofSiOz, about 23% by weight B203, about 7% by weight` NaO and about byweightAlzOa. Other examplesof suitable boro-silicateY glass which. may.A be employed in practising this invention and; different Kovar alloys which'. may be employedtherewith within the range given hereinbefore and contemplated withinthe scope ofV thisinventionmay be readily ascertained by reference to-Patent- No. 2,062,335, issuedA December 1, 1936, toHoWar-d Scott. With the stack thus. formed-having the glasswashers (not shown) disposed betweenadjacent conductor leaves, a top plate 30.hav-ing openings therein. corresponding to:V the openings formed in the annular members22, 24: and-26 is placed upon the stack, the ceramic tubes` 28 and carbon. rod (not shown) positioning the-plate 3l!v whereby the central opening in. theA platev will lform a continuation of. the Well formed bythe aligned openings in the conductor membersI Zand spacing members I4. Suitable-elongatedbolts-32- are then positioned Within thev ceramic tube- 28,- the assembly being clamped into atight assembly by means of tightening theA nuts 34associated with each of the bolts 32.

In preparing the conductor members I2 for sealing, they are preferably preoxidized at a1 temperature of about 800 C. for three minutes prior to forming the stacked assembly. With. the stack held tightly by means of the bolts 32, the assembly isplaced in a heatingv furnace which has previously been flushed With nitrogen and the furnace temperature israised to about 1050 C., while maintaining a nitrogen atmosphere. The; stacked' assembly. isfheld-at this temperature v for a period of time of about 30 minutes after which it is cooled to approximately 500 C. when hydrogen is admitted. The temperature is then reduced to about 450 C. Where it is held for a period of time of one hour to anneal the seal formed by the glass washer having melted and bonded to the conductor members I2 and the ceramic insulating members I4. When the assembly is removed from the furnace, it is found that the glass washer has melted and the glass has flowed as illustrated at 36 in Fig. 3 effectively bonding with the conductor members I2 and the spacer members I4 as well as bonding to each of the ceramic tubes 28. It is further found that theY glass also bonds to the top plate 30 and the annular member 22 of the base portion.

After the glass is bonded to the ceramic tubes 28., the tubes 28 cease to function as guide members and are now found to be an integral part of the alternately stacked assembly effectively reenforcing the assembly and rendering it resistant to mechanical shock. The bolts 32 mayor may not be retained in the assembly as desired but usually they are left Within the ceramic tubes 28 to further reenforce the structure and; aid in maintaining the seal; between the conductor members and spacer members. The carbon rod is removed from thel 4central: opening -after the bond is-completed;

Referring to Fig. 2, itisseen that the annular member 26 forming the bottom portion of the base is provided with an'v annular depending flange member 38` positioned about the central opening formed-1 in theA plate. posed4 at the lower end of the stacked assemblsT and is provided?A with an annular ring- 42 which'is sealed byanysuitable means such asby a weldor solder to thev depending flange member 38'A of the plate 26 for forming a receptacle for ali'quid conducting material, such asmercury 43;

At the other end of the assembly, asealed-gas chamber 44 havingaV downwardly projecting flange 46 is sla-disposed with respect tothe central opening in the top plate 3Dland'1wel'dedlto the top plate that the flange 46 is in alignment with thel well formed in the'. stacked'I assembly. In practice, an opening, notshown, is initiall'yprovided in the gas chamber for evacuating the sealed Well which communicateswith both the bellows Mlandv the gas chamber 44. After evacuating thewella predetermined amount `of mercury is introduced! into the bellowsy 40 and I a1 nonoxidizingV4 gasandpreferably a gas-such as hydrogen, is introduced into the spacer abovethe mercury. The gas functions-to'prei'zentvorI reduce arcing between theA edges of the sp-acedconductor leaves forming; the wallIV oftheA common well. After the gas-has' been introduced' into the gas chamber, thegaschamber` is sealedA frorrrthe atmosphere.

InA addition to reducing the arcing` between theY conductor members, itis found that the gas acts as a cushion on the. column of mercury when it i3 forced through the well'4 by pressureapplied externally ofthe bellows and at times-the. gas chamberY functions to. receive the. mercury as well asthegas. As;wi1lbe understood, pressure canbe` applied' to` the, bellows.- by any suitableY means for forcing the-mercury.l contained within the, bellows upwardly: throught-he swell? to profgressively. bridge; the; spaced conductor. members in accordance withthe amount' of. pressure applied, it-being found that a veryslight movement oflthe: bellows is effective'A for moving the mercuryV A- bellows 40lis-di'scolumn through the well to progressively contact the conductor leaves.

Referring to Fig 4, there is illustrated a regulating system which utilizes the switching apparatus of this invention. In this system, a generator 48 is shown, the voltage of which it is desired to maintain constant. 'Ihe generator 48 may be driven from any suitable source of power, such as a motor (not shown) and comprises the armature windings 50 and the shunt eld windings 52. Connected in .series with the shunt eld winding 52 is a rheostat 54 formed of a plurality of sections disposed to be cut in or shunted from circuit with the field winding 52. In order to control the number of sections of the rheostat 54 which are cut in circuit with the eld winding 52, the switching apparatus l of this invention is disposed with its staggered conductor members l2 so connected by leads 55 to the different sections of the rheostat 54 that as the column of mercury is forced upwardly through the well, it progressively bridges the leaves l2 to shunt additional sections of the rheostat 54.

In order to control the operation of the switching apparatus I0, an electromagnet comprising a core member 58 and winding 58 and a movable armature member 80 are so associated with the switching apparatus I5 that as the voltage of the generator 48 increases, and consequently the energization of the winding 58 increases pressure' on the bellows 40 is decreased to permit the mercury column to fall within the well of the apparatus of Figs. 1 and 2, whereby more of the sections of the rheostat 54 are cut in circuit with the eld winding 52 to decrease itsenergization and consequently decrease the generator voltage. The armature 60 is preferably connected directly to the bellows 40, a spring 6I being provided to actuate the bellows upwardly when the winding 58 is deenergized. Thus, if the voltage output of the generator 48 decreases, the energization of the winding 58 is decreased and the spring 8| actuates the bellows 40 upwardly to effectively kforce the mercury into the well to progressively bridge the conductor members l2 and thereby progressively shunt additional sections of the rheostat 54 from circuit with the field winding 52, thereby increasing the energization of the field winding 52 and increasing the voltage of the generator 48.

The switching apparatus of this invention is very efficient, only very small movement of the I bellows being necessary for effecting a switching operation. Further, a large number of switching operations can be accomplished with very little equipment since the apparatus of this invention contemplates a large number of conductor members in a small space. Further, the apparatus of this invention is capable of carrying relatively large current since the conductor members are in effect heavy terminals. Large conductors may be attached to the conductor members of this apparatus since the leaves are so shaped and staggered that by reversing the conductor members in assembling them, as described hereinbefore there is, in eifect, eight rows of terminals obtained which although the conductor members are quite close and can readily be bridged by slight movements of the mercury column, nevertheless gives ample room for connecting or attaching large conductors to the tapered ends of the conducting leaves.

Although this invention has been described with reference to a particular embodiment thereof, it is, of course, not to be limited thereto except ducting medium, means associated with the conductor members and the spacer members for holding them alternately assembled, and a bonding material applied to bond the conductor members, spacer members and holding means and provide sealed side walls for the well, the holding means bonded to the conductor members and spacer members rendering the bonded structure resistant to shock.

2. In a sealed switching apparatus provided with a liquid conducting medium for eiecting a switching operation, in combination, a plurality of conductor members disposed in spaced relation, a plurality of insulating spacer members stacked alternately with the conductor members, each of the conductor members and the spacer members having an opening therein aligned to provide a well in the stack for receiving the conducting medium, a plurality of elongated members disposed in spaced relation to each other and extending through the conductor members for holding the conductor members and the spacer members in assembled relation, and a bonding material applied to bond the conductor members, spacer members and the spaced elongated members and provided sealed sidewalls for the well, the elongated members bonded to the conductor members and the spacer members rendering the bonded structure resistant to shock.

3. In a sealed switching apparatus provided with a liquid conducting medium for effecting a switching operation, in combination, a plurality of conductor members disposed in spaced relation, a plurality of insulating spacer members stacked alternately with the conductor members, each of the conductor members and the spacer members having an opening therein aligned to provide a well in the stack for receiving the conducting medium, the spacer members having a predetermined thickness and being smaller in surface area than the conductor members so that when assembled the conductor members project outwardly beyond the edges of the spacer members, a plurality of elongated members disposed in spaced relation about the spacer members and extending through the conductor members, and a bonding material applied to bond the conductor members, spacer members and the elongated members and provide sealed side walls for the well, the elongated members bonded to the conductor members and the spacer members rendering the bonded structure resistant to shock.

4. lIn a sealed switching apparatus provided with a liquid conducting medium for eifecting a switching operation, in combination, a plurality of conductor members disposed in spaced relation, a-plurality of insulating spacer members stacked alternately with the conductor members, each of the conductor members and the spacer members having an opening therein aligned to provide a well in the stack for receiving the conducting medium, a plurality of rods disposed in spaced relation to each other and extending through the conductor members for holding the spacer members and conductor members in assembled relation, mea'ns associated with each of the rods for insulating them from the conductor members, and a bonding material applied to bond the conductor members, spacer members and rod insulating means into a sealed integral structure, the rod insulating means bonded therein reinforcing the sealed assembly and rendering it resistant to shock.

5. In a sealed switching apparatus provided with a liquid conducting medium for effecting a switching operation, in combination, a plurality of conductor membersdisposed in spaced relation, the conductor members being composed' of an iron base alloy having a nickel plus cobalt content of between 40 to 55% with the cobalt ranging' from about l2 to 33%, a plurality of ceramic insulating spacerv members stacked alternately with the conductor members, each of the conductor members and spacer members hav-l ing an opening therein aligned to provide a Well in the stack for receiving the conducting medium, mea-ns associated with the conductor members and spacer members for holding them alternately assembled, and means comprising a boro-silicate glass having a c'o-elcient of expansion approximating that of the conductor members applied to bond the conductor members, spacer members and the holding neans into a sealed integral structure, the holding means bondedv therein reinforcing the sealedv assembly andl rendering 1t resistant to shock.

KIRK A; OPLINGER. 

